CVE-2025-40052

Kernel crash via non-linear AEAD context allocation

Published Oct 28, 2025 · Updated Oct 28, 2025

Denial of service in the Linux kernel SMB client allows local users to crash the kernel through encrypted-mount I/O. The crypt_message function allocates the AEAD request with kvzalloc, which can place its private context in vmalloc memory even though sg_set_buf requires linear memory. Systems with CONFIG_VMAP_STACK enabled reach the failing address range under many parallel reads and writes on an encrypted SMB mount, causing a kernel BUG and service interruption.

CVSS severity6.2
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel SMB client allows local users to crash the kernel through encrypted-mount I/O. The crypt_message function allocates the AEAD request with kvzalloc, which can place its private context in vmalloc memory even though sg_set_buf requires linear memory. Systems with CONFIG_VMAP_STACK enabled reach the failing address range under many parallel reads and writes on an encrypted SMB mount, causing a kernel BUG and service interruption.

The record

CVE
CVE-2025-40052
Published
Oct 28, 2025
Updated
Oct 28, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.3
  2. Affected versionversion=d08089f649a0cfb2099c8551ac47eef0cc23fdf2 <4a61b68abd2788db0364c9a0b6a39f1699fea440
  3. Affected versionversion=d08089f649a0cfb2099c8551ac47eef0cc23fdf2 <7a8a8c15468f0c99685e9964451feffd1a3cc859
  4. Affected versionversion=d08089f649a0cfb2099c8551ac47eef0cc23fdf2 <998a67b954680f26f3734040aeeed08642d49721
  5. Affected versionversion=d08089f649a0cfb2099c8551ac47eef0cc23fdf2 <ba905a567105dde21cdb8e6d3a87110fa434b393

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.3; version=d08089f649a0cfb2099c8551ac47eef0cc23fdf2 <4a61b68abd2788db0364c9a0b6a39f1699fea440; version=d08089f649a0cfb2099c8551ac47eef0cc23fdf2 <7a8a8c15468f0c99685e9964451feffd1a3cc859; version=d08089f649a0cfb2099c8551ac47eef0cc23fdf2 <998a67b954680f26f3734040aeeed08642d49721; version=d08089f649a0cfb2099c8551ac47eef0cc23fdf2 <ba905a567105dde21cdb8e6d3a87110fa434b393

Published CVSS scores

6.2Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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